[The operant word is expect — not desire or deploy. I might think that such an app (whether needed now or not) would be a desideratum, but I wouldn't a priori guess that such might be available and therefore go looking for such.
How well organized the 1,500,000 iPhone apps are in the App Store is arguable, but Apple does a good job of identifying and highlighting new useful apps. I have found at least a couple that I did not know I needed and I was not looking for until Apple highlighted them on the App Store and have since become absolutely invaluable to me.
The most obvious example of such an app is Evernote®. I did not know I needed it. I could not even envision how I might use it. Now it is the key element in my workflow and records management.
